The present invention relates to a display control apparatus and a display control method for controlling the brightnesses of a screen to be displayed on a display that is installed on a vehicle and backlight.
In general, when the driver inserts an ignition key into a key cylinder and turns it to start a vehicle, a battery switch, an accessory switch and an ignition switch become on sequentially, and with a starter motor operated an engine is activated. In vehicles equipped with an air suspension system, there are some vehicles in which the air suspension system is activated after a certain period of time has elapsed since the accessory switch is turned on. In this case, an image showing an operating state of the air suspension system is displayed on the display portion, whereby the driver is informed of the current operating state of the air suspension system.
Hereinafter, a conventional operation procedure of activating a vehicle will be described by reference to a flowchart shown in FIG. 5.
Firstly, when the driver inserts the ignition key into the key cylinder and turns the key, the battery switch is placed in an ON position, whereby a battery installed in the vehicle is connected to ECUs or various types of measuring instruments or gauges (step S101). Then, a CPU starts to operate (step S102).
The ignition key is turned to an accessory position, and it is determined that whether or not the accessory switch is turned on (step S103). If the accessory switch is not turned on (NO in step S103), the CPU is shifted to a low power consumption mode, so as to reduce the consumed power (step S104).
On the other hand, if it is determined that the accessory switch is turned on (YES in step S103), a standby mode of the CPU is canceled (step S105), whereby the operation of the air suspension system is started (step S106).
A power supply of a display is switched on (step S107), and further, the operation of the display is started, whereby a backlight of the display portion is illuminated (step S108).
It is determined that whether or not the ignition switch is turned on (step S109), and if it is determined that the ignition switch is not turned on, the flow of the operation procedure is returned to the operation in step S108.
On the other hand, if the ignition switch is determined to have been put on, an operation or operations relevant to the ignition switch being on are executed (step S110), and further, the vehicle starts to operate normally (step S111).
Here, as described above, since the air suspension system is activated after the accessory switch is turned on, in a case that the ignition switch is still not turned on even after a long period of time has elapsed since the air suspension system started to operate, with the engine started to operate, an operating state of the air suspension system is kept displayed on the display. As this occurs, the consumed power by the display portion which keeps displaying the operation state of the air suspension system is increased, which causes a problem that large load of the battery occurs.
In addition, JP-A-2007-121408 (Patent Document 1) describes a liquid crystal display apparatus which realizes a backlight which can save electric power to be consumed. However, nothing is described therein on means or method for reducing the consumed power before the ignition switch is turned on.
[Patent Document 1] JP-A-2007-121408
As described above, with the conventional display control apparatus, there exists the drawback that when displaying on the display an image such as one showing the operating state of the air suspension system before the ignition switch is turned on to start the engine, large electric power is required and large load of the battery occurs. Thus, there have been increasing demands on reduction of the consumed power by displaying the image before the ignition switch is turned on.